Magnetic recorder and drive therefor



Feb. 6, 1945. M, CAMRAS 2,369,017

MAGNETIC RECORDER AND DRIVE THEREFOR Filed Feb. 25, 1945 3 Sheets-Sheet1 MARV/N UAMRAS M. CAMRAS 2,369,017

MAGNETIC RECORDER AND DRIVE THEREFOR Filed Feb. 25, 1943 s Sheets-Sheet2 Feb. 6, 1945.

MARI/IN a m IRAS 6 1 z 6 m D \n,

Feb. 6;; 1945. M.'CAMRAS MAGNETIC RECORDER ANDDRIVE THEREFOR Filed Feb.25, 1943 s Sheets-Sheet s Patented Feb. 6, 1945 MAGNETIC RECORDER ANDDRIVE THEREFOR Marvin Cami-as, Chicago,

Research Foundation,

tion of Illinois 111., assignor to Armour Chicago, 111., a corpora-Application February 25', 1943, Serial No. 477,056

sclaims.

This invention relates to improvements in a magnetic recorder and drivetherefor, and more particularly to a magnetic recorder highly desirablefor use in a home, office or similar location, although the inventionmay have other uses and purposes as will be apparent to one skilled inthe art.

More specifically, the present invention is designed to be in a magneticrecording device wherein a sound recording is made by successive- 1ymagnetizing increments on an elongated recording medium such as a tapeor wire of para magnetic material. Such recording may also be reproducedby the device and, if so desired, the device may be constructed torecord only, or to reproduce only.

It is an object of the instant invention to provide an economical andsimple form of drive mechanism for such a recording machine.

Another object of the invention resides in the provision of drivemechanism for a magnetic recording or reproducing machine, with themechanism so arranged that there is at all times a smooth friction driveduring operation.

Also an object of the invention is the provision of a magnetic recordingor reproducing device embodying a drive mechanism in which the mountingof the power element is such as to give a smooth start with no jerks.

It is also a'feature of the invention to provide a magnetic recordingand reproducing device embodying a drive mechanism of a simplified andeconomical character in which the direction of drive is changed by abodily movement of the power element, and in which the reverse drive maybe faster than the forward drive.

Also a feature of the invention resides in the provision of a magneticrecording and reproducing device including a drive mechanism which notonly drives the moving parts of the device, but which also automaticallyprovides a braking action when it is desired to stop the device.

Still another object of the invention resides in the provision of adrive mechanism for a magnetic recording and reproducing device whereinbodily movement of the power element causes forward or reverse drive,and also provides a braking action when stopping or shifting from onedirection to the other.

A further feature of the invention resides in the provision of a drivingarrangement for a magnetic recording or reproducing device wherein thepower element automatically drives the moving parts and applies abraking action to the moving parts when it is desired to stop, by meansof the same element.

Still another object of the invention resides in the provision of adrive mechanism for a magnetic recording or reproducing device, whichmechanism not only drives during operation, but applies a braking actionwhen it is desired to stop operation, and the arrangement is such thatthe energizing force must be oil the driving element when the brakingaction is applied.

Another object of the invention is the provision of a drive mechanismfor a magnetic recording and reproducing device wherein an electricmotor is utilized as the power element, and the motor is so mounted thatit will pivot in one direction for a forward drive, pivot in anotherdirection for a reverse drive, and pivot in-still another direction toelfect a braking action upon cessation of operation.

While some of the more salient features, characteristics and advantagesof the instant invention have been above pointed out, others will becomeapparent from the following disclosures, taken in conjunction with theaccompanying drawings, in which:

Figure 1 is a front elevational view of a magnetic recording deviceembodying principles of the instant invention, showing the same with thecover in elevated or open position;

Figure 2 is an enlarged fragmentary plan sectional view of the structureof Figure 1, taken just inside the top of the casing;

Figure 3 is a fragmentary vertical sectional view of the structure takensubstantially as indicated-by the line III-III of Figure 1, looking inthe direction of the arrows;

Figure 4 is a fragmentaij plan sectional view taken substantially asindicated by the line IV-IV of -Figure 3, illlwtratingfthe controlswitch diagrammatically and ,with. a lchematic wiring d ini added;

Figure '5 is a vertical sectional view through the forward partof thecasing, illustrating the structure of Figure 4 in front elevation;

Figure 6 is a fragmentary plan sectional view taken just beneath thedriving disk of Figure 5, and showing the structure of Figure 5 in plan;and

Figure 7 is a fragmentary vertical sectional view, with parts inelevation, taken through the control switch of Figure 2.

As shown on the drawings:

In the illustrated embodiment of the instant invention, there is shown amagnetic recording device including a cabinet I made of wood, metal,

or any other suitable material, which is so constructed as to box inthedriving mechanism as well as all of the required electrical circuits andapparatus. With reference to Figure 3, it will be seen that a platform 2is provided in the forward portion of the cabinet, and over thisplatform is a door or drop closure 3 hinged to remainder of the cabinetas indicated at '4, the drop cover being shown in open position inFigure 1 and in closed position in Figure 3.

Disposed over the upper surface of the platform 2 so as to be accessiblewhen the cover 3 is raised are a spool or reel adjacent one side of thecabinet, and a similar spool or reel 6 adjacent the opposite side of thecabinet. The spool 5 is carried on a shaft 1, and the spool B on a shaft8, which shaft extends through the platform 2. The spools carry arecording medium, which in the illustrated instance is in the form of afine round wire 9, and this medium may be wound backfor the wire. As thewire leaves the spool 5, it first passes through a level winding element10, thence through an erasing head or demagnetizing element II which maybe in the nature of a high frequency coil, then over a guide pulley I2,through a recording or magnetizing head l3, over another guide pulleyl4, through another level winding element l5, and on to the spool 6.

In making a recording, it is not necessary to use a clean wire which maybe either a completely demagnetized wire or a uniformly magnetized wire.A wire with a recording already thereon may be used, and as it passesthrough the erasing head I I, the wire will be demagnetized so that itwill be clean before it reaches the recording head I3 in whichsuccessive small increments of the wire are magnetized in accordancewith the sound production being recorded.

In operating the recorder, the wire is traveling forwardly, or from thespool 5 to the spool 6, during the making of a recording. The sound ispicked up by a microphone or any other suitable pick-up device, andthrough a suitable amplifying and oscillating circuit the recording headI3 is energized in accordance with variations of the sound so picked up.Such electrical circuits are contained within the cabinet I, but neednot be described herein. After a recording has been made, the wire iswound in reverse direction, from the spool 6 onto the spool 5.Thereafter, the wire is again moved forwardly, the erasing head is notfunctioning, and the recording head then acts as a pick-up deviceresponding to the various magnetizations on the wire, the recording headthen being in circuit with a suitable loud speaker circuit so that thereproduction may be heard through a loud speaker opening IS in theforward portion of the cabinet as seen in Figure 1. The loud speakercircuit is also contained within the cabinet but need not be describedin connection with the instant invention. It will be appreciated thatthe spools may be changed whenever desirable, recordings preserved byremoving the spool and filing it away until it is desired to be usedagain, or recordings may be made, reproduced, and then a new recordinsubstituted on the sa e wire for the previous recording, just as theuser may desire.

The present invention centers itself more particularly with the drivingmeans for operating the spools. It will be appreciated that the wire isusually a very fine wire, substantially the siz of a human hair,approximately .004 or .005 inch in diameter being a satisfactory sizefor the wire. Accordingly, it is desirable to start and stop smoothlyand without jerks so as not to put any undue strain upon the wire, andto prevent wastage of the wire due to over-run or coasting of the idlingspool. When the wire travels forwardly, namely, from the spool 5 to thespool 5, the spool 6 will be the driven spool and the spool 5 will beidling. When the wire travels in reverse direction, the contrary istrue, and the spool 5 will be driven while the spool 6 is idling. Thepulleys l2 and I4 are mounted on stub shafts and idle at all times,being rotated merely by the friction of the traveling wire. The levelwinding elements In and I5 may be operated by any suitable mechanismwhich need not be described herein.

The driving mechanism for the reels or spools 5 and 6 is carried withinthe cabinet I, and includes a powerelement which may be in the form ofan electric motor l1. This motor is specially mounted to permit pivotalmovement along an arcuate path toward each side of the cabinet from itsstationary position, and also permits pivotal movement of the motor in adirection toward the rear of the cabinet when it is desired to stopoperation.

With reference more particularly to Figure 3; it will be seen that themotor is mounted at the forward end on a ball l8 seated in a suitablesocket in the motor casing and also in a suitable socket in a bracket I9upstanding from a base member 20 fixed to the bottom of the cabinet. Onthe rear side, the motor casing is equipped with a fixed block or pillow2| having an arcuate surface 22, the center of which is preferably atthe center of the ball I8. This block 2| bears against a block 23 havingan arcuate face complemental to the face 22, the block 23 being carriedon the inner end of .a bolt 24 extending through a bracket 25 upstandingfrom the base 20 and. which bolt may be adjusted by a suitable nut 24aon the outside of the bracket. It is therefore apparent that the motoris in effect suspe ded tween the ball l8 and the block 23 and is free toswing from side to side in iooth directions and from front to rear onthe arcuate faces of the ball and the block 2|.

The motor shaft 26 extends upwardly from the motor and on its upper endcarries a friction drive disk 21 having an inclined driving edge 21a, asbest seen in Figure 5. This drive disk 21 may engage another disk 28carried on the lower end of the shaft 1 from the spool 5 either togetherwith or separately from another and larger disk 29 carried on the lowerend of the shaft 8 from the spool 6. If the disk 21 is in engagementwith the disk 28 only, the wire is driven in the rewind direction,namely, from the spool 6 to the spool 5, the spool 5 being the drivenspool and the spool 6 the idling spool. If the disk 21 engages only thedisk 29, the Wire is driven in forward direction, the spool 6 being thedriven spool and the spool 5 being the idling spool.

If the drive disk 21 engages both the disks 28 and 29 at the same time,an automatic braking action results, thus providing a quick, even, andrelatively gentle stopping of operation of the spools. It will be notedthat the driven disk 29 travel of the wire in a forward or recordingdirection is at a lower speed than the travel of the wire in reverse ,orre.-wind direction. This obviously saves time in the re-windingoperation when the wire is merely being made ready for a recording or areproduction.

When the device is -at rest and the motor is not in operation, a spring2| attached at one end to the motor casing and at the other end to a pin3| extending downwardly from the platform 2 pivots or swings the motorin its rearward direction so that the disk 21 simultaneously contactsboth driven disks 22 and 26 to thereby apply the braking action. When itis desired to resume operation, the motor is pivoted or swung sidewiseso that it contacts only the disk 26 or the disk 29. depending upon thedesired direction. This sidewise movement of the motor is, of course,against the action of the spring 3|! and is obtained with the aid ofmeans now about to be described.

With reference more particularly to Figures and 6, it will be seen thaton one side of the motor-casing a paramagnetic block 32 is mounted,which block functions as an armature for an electro-magnet 33 disposedat a slight angle to the motor and carried in one or more suitable clips34 attached to the aforesaid base member 20. When the electro-magnet 33is energized, the motor will swing to the dotted line position seen inFigure 6 where the paramagnetic block 32 is adjacent the end of themagnet. In this position, the driving disk 21 is in contact only withthe driven disk 29 so that the mechanism will operate forwardly and thewire will travel from spool 5 to spool 6. When the magnet 33 isenergized, the motor will be in rearward position by the action of thespring 30 with the disk 21 in contact with both the disk 28 and the disk29. Upon energization of the magnet 33, the motor will move laterallyalong an arcuate line of travel and the disk 21 will roll over the edgeof the disk 29 out of contact with the disk 26 and effect a drive of thedisk 29 through a contact point further forward than is seen in Figure4.

On the other side of the motor is a similar paramagnetic block 35, and asimilarly disposed 'electro-magnet 36 carried in one or more clips 31.

When the electro-magnet 36 is energized, the motor will swing to thefull line position of Figure 6, against the action of the spring 30, thedisk 21 rolling over the edge of the disk 26 out of contact with thedisk 29, and a drive in the reverse contact 42, thence through aconductor 44- into the motor windings, and returns from the motorwindings through conductor 45 to theopposite line conductdr 46. Theelectromagnet 33 is likewise energized by current, passing from the lineconductor 4| through the switch blade to contact 43, thence through aconductor 41- into the coil of the magnet, and returns from the coilthrough a conductor 48 to the opposite line conductor 46.

This operation both energizes the motor and causes it to be swung alongan arcuate path to the right against the action of the spring 30 so thatthe driving disk 21 will contact only the larger driven disk 29 andoperate the mechanism in a forward direction.

When the switch is swung to the left, as also indicated by dotted linesin Figure 4, the switch blade will engage a pair of contacts 49 and50.The motor will be energized in the manner above described by currentpassing from the line conductor 4| through the switch blade and into themotor through conductor 44, returning through conductor 45 to theopposite line conductor 46. At the same time, the electro-magnet 36 willbe energized by current passing from line conductor 4| through theswitch blade to contact 50, and thence into the magnet through 5|,returning to the opposite line wire through conductor 52. When theswitch is so moved, the motor will be energized, and due to theelectro-magnet 36 the motor will be swung bodily through an arcuate pathto the left so that the drive disk 21 will contact the smaller drivendisk 28 and operate tro-magnet was first energized, permitting thespring 30 to pull the motor into braking position with the disk 21 incontact with both the disks 28 and29 and thus effecting a firm butdirection will be effected through a point of contact between the disks21 and 26 forward of the position seen in Figure 4.

The operation of the magnetic recording machine is controlled through aswitch 38 which may be thrown either to the right or left from theneutral position seen in Figure 2. When thrown to the right, the wire 9travels forwardly, and when the switch is thrown to the left, the wire 9travels in the reverse or re-wind direction. With reference to Figure 7,it will be seen that the switch includes a shaft 39 which on its lowerend carries a switch blade 40, one end of which is connected in anysuitable fashion to a line conductor 4| emanating from any suitablesource of electric current. When the switch is thrown to the right asindicated by dotted lines in Figure 4, the switch blade 4|!simultaneously contacts a pair of contactors 42 and 43 which are spacedapart one from the other. The motor I1 is energized for operation bycurrent passing from the line conductor 4| through the switch blade togentle and complete stopping of operation before operation can bestarted in the reverse direction. This, of course, avoids any suddenjerk upon the wire or magnetizing medium 9, and prevents wastage'of wireby stopping undesirable over-run or coasting of the idling spool.

From the foregoing, it is apparent that I have provided simple andeconomical driving mechanism for incorporation in a-magnetic recordingor reproducing machine, which mechanism not only is capable of drivingthe movable parts of the recording machine in both forward and reversedirection, but also automatically applies'an effective braking actionwhen the machine is stopped or when it is desired to-shift from onedirection of motion to" the other. It will further be appreciated thatthe drive in both directions as well as the braking action are eifectedby the power element itself, and that the element is so arranged as torender it impossible to change direction of operation without thebraking action becoming eifective so that there is no undue tensionplaced upon the recording medium and no wastage of such medium. Further,the drive is even and smooth in character, and starts and stops may bemade without jerks or similar abrupt motion.

It will, of course, be understood that various details of constructionmay be varied through a wide range without departing from the principlesof this invention and it is, therefore, not the purpose to limit thepatent granted hereon otherwise than necessitated by the scope of theappended claims.

I claim as my invention:

1. In a magnetic recordingdevice, a pair of rotatable spools from one tothe other of which a paramagnetic recording medium may travel, a powerelement, a friction disk carried on the shaft of said power element, afriction disk carried on the shaft of each of said spools, and means toshift the power element bodily to cause its friction disk tosimultaneously engage both the spool disks to establish a braking actionupon de-energization of the power element.

2. In a magnetic recording device, a pair of rotatable spools from oneto the other of which a paramagnetic recording medium may travel, apower element, a friction disk carried on the shaft of said powerelement, a friction disk carried on the shaft of each of said spools,means to hold said power element in such position that its friction diskcontacts both said spool. disks when at rest, and means to pivot saidelement bodily through a lateral but arcuate path to cause its disk toroll over one of the other disks out of contact with theremaining diskand drive. said one disk.

-on the shaft of said element, resilient means 3. In a magneticrecording device, a pair of rotatable spools from one to the other ofwhich a paramagnetic recording medium may travel, a power element, afriction disk carried on the shaft of said, power element, a frictiondisk carried on the shaft of each of said spools, means to hold saidpower element in such position that its friction disk contacts both saidspool disks .when at rest, means to pivot said element selec- -aparamagnetic recording medium may travel, a

friction disk on the shaft of each of said spools,

holding said drive element in position with the drive disk in contactwith both said friction disks, a paramagnetic member on each of oppositesides of said drive element, and an electro-magnet disposed obliquely tothe power element opposite each of said paramagnetic members, each suchelectro-magnet when Y energized causing said power element to swingthrough an arc laterally against the action of said resilient means tohave the drive disk in engagement with only one of said friction disks.

5. In a magnetic recording device, a pair of rotatable spools from oneto the other of which a paramagnetic recordingmedium may travel, afriction disk on the shaft of each of said spools, a pivotally mountedpower element, a drive disk on the shaft of said element, resilientmeans holding said drive element in position with the drive disk incontact with both said friction disks, a paramagnetic member on each ofopposite sides of said drive element, an electro-magnet disposedobliquely to the power element opposite each of said paramagneticmembers, each such electromagnet when energized causing said powerelement to swing through an arc laterally against theaction of saidresilient means to have the drive disk in engagement with only one ofsaid friction disks, and control means for said electromagnet soarranged that only one magnet may be energized at a time and so that thepower element is tie-energized each time an electromagnet istie-energized.

6. In a magnetic recording device, a pair of spaced rotary reels fromone to the other of which a paramagnetic recording medium may travel, apower element, a friction disc carried on the shaft of said powerelement, a friction disc associated with each of said reels, electricalmeans arranged to move said element bodily to cause it to drive eitherof said reels through the first said friction disc and the respectivereel disc, and other means associated with said element to move it insuch position that the first said friction disc simultaneously contactsboth the reel discs to provide a braking action upon deenergization ofsaid electrical means.

MARVIN CAMRAS.

